A solid electrolytic capacitor consists of a valve metal anode, a dielectric layer that is usually an oxide of the valve metal, an electrolyte layer that is typically formed from a conductive polymer and is positioned over the dielectric layer. A cathode layer is positioned over the electrolyte layer and the structure is encapsulated in a dielectric plastic.
For optimum usage, the electrolytic capacitor must have low current leakage and be resistant to external stresses. Significant current leakage can result if the adhesion between the electrolyte layer and the dielectric layer fails. Also, series resistance across the interface between the dielectric layer and electrolytic layer can be minimized by improved adhesion and wetting. If the capacitor is subjected to external stresses, the adhesion between these layers may suffer, and the series resistance can increase. Therefore, it would be desirable to enhance the adhesion between the conductive polymer layer and the dielectric layer.